Epi
Test Sensitivity
search
Test Sensitivity
, False Negative Rate
See Also
Screening Test
Contingency Grid
or
Cross Tab
(includes
Statistics Example
)
Bayes Theorem
(
Bayesian Statistics
)
Fagan Nomogram
Experimental Error
(
Experimental Bias
)
Lead-Time Bias
Length Bias
Selection Bias
(
Screening Bias
)
Likelihood Ratio
(
Positive Likelihood Ratio
,
Negative Likelihood Ratio
)
Number Needed to Screen
(
Number Needed to Treat
,
Absolute Risk Reduction
,
Relative Risk Reduction
)
Negative Predictive Value
Positive Predictive Value
Pre-Test Odds
or
Post-Test Odds
Receiver Operating Characteristic
Test Specificity
(
False Positive Rate
)
U.S. Preventive Services Task Force Recommendations
Definition
Screening Test
's ability to identify true disease
A Test with high sensitivity has few false negatives
Independent of disease
Prevalence
in the community
Sensitive Tests allow user to rule out a condition (mnemonic "SNout")
Calculation
Test Sensitivity
True positive tests per total affected patients tested
Test Sensitivity = P(positive test | disease)
Where P (A | B) = Probability of A given B
Expressed as a percentage
False Negative Rate
True cases missed by the
Screening Test
(test negative despite presence of condition)
False Negative Rate = 1 - Test Sensitivity
Example
A new
Screening Test
for
Crohn's Disease
Patients with known
Crohn's Disease
tested: 45
Patients with known
Crohn's Disease
who have a positive test: 36
Sensitivity = 36/45 or 80%
References
Hennekens (1987) Epidemiology Medicine, p.327-47
Gates (2001) Am Fam Physician 63(3):513-22 [PubMed]
MacLean (1996) Med Clin North Am 80(1):1-14 [PubMed]
Nielsen (1999) Med Clin North Am 83(6):1323-37 [PubMed]
Type your search phrase here